Psoas compartment block for treatment of motor weakness and pain following herpes zoster

Reactivation of the latent varicella zoster virus in the sensory ganglion causes herpes zoster (HZ). Its characteristic symptom is a painful rash in the involved dermatome. HZ-induced motor weakness is rare and is usually resolved within one year of the onset, but some patients permanently experience motor dysfunction. Epidural steroid administration, with antiviral therapy, can be effective in treating pain from HZ and preventing postherpetic neuralgia. But an epidural block is contraindicated in patients receiving thromboprophylaxis. A psoas compartment block (PCB) provides equivalent analgesic efficacy with significantly low incidence of complication, compared to an epidural block. A 68 year old male patient recieving thromboprophylaxis presented with motor weakness following painful rash in his left L4 dermatome. Ten days before presentation, herpetic rash occurred on his left leg. We performed PCB with a steroid and local anesthetic, which successfully and safely alleviated the pain and motor weakness from HZ.